Plant systems will be exposed to medical ultrasound (2 MHz, 1-20 W/cm2) and analyzed for induction of perturbations. The parameters to be analyzed include growth, cell kinetics, and macromolecular synthesis (DNA, RNA and protein). Correlations will be sought between these parameters and the applied ultrasound. DNA molecular weight analyses of sonicated plant cells will also be undertaken to determine if the sound induces DNA strand breakage. Additionally, growth and cell kinetic analyses will be utilized in experiments designed to determine if acoustic cavitation is a physical mechanism responsible for induction of perturbation in these two biological parameters. Dose fractionation experiments will attempt to determine if ultrasonically-induced lesions are reparable.